Liu Jia-Ying, Yan Pei-Hua, Yang Zeng-Ren, Sun Fang-Ren, Shan Qiu-Ling, Li Yu-Qing
Institute of Healths and Environmental Medicine, Academy of Military Medical Sciences, Tianjin, China).
Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2009 Feb;25(1):117-20.
To investigate the effects of shivering on airway rewarming.
The hypothermic dog model without shivering was established by immersing an anesthetized dog in cold water and administering atracurium to inhibit the dog shivering. The model dog respired warm fully humidified (40-45 degrees C, RH 99.9%) air and room temperature air(19 +/- 1 degrees C, RH 30% - 75%) to rewarm each for 2 hours, the priority of different temperature air respired was arranged randomly. After rewarming for 4 hours, the relaxed dog breathed warm humidified air by positive pressure ventilation in order to restore its spontaneous respiratory. Then the dog continued to respire warm humidified air spontaneously until the esophageal (Te) and rectal temperature (Tr) of the dog achieved the same degrees as the dog was immersed in the water. The metabolic heat production was detected by indirect calorimetry during the experiment.
(1) When the shivering was inhibited, inhaling warm humidified air for 2 hours made the Tr and Te of the dogs increase 0.26-0.39 degrees C and 0.44-1.11 degrees C per hour respectively, inhaling air at room temperature for 2 hours made Tr and Te of the dogs decrease 0.24-0.51 degrees C and 0.58-0.67 degrees C per hour, respectively. And the changes in Tr and Te of the dogs were unrelated to the priority of inhaling air at different temperature. (2) When the dog with shivering respired spontaneously warm humidified air, the rewarming rates of Tr and Te were 2.26-2.33 degrees C/h and 1.96-2.38 degrees C/h respectively, quicker than those of the dogs whose shivering was inhibited. (3) Compared with metabolic heat production of the unshivering dog respiring warm humidified air by positive pressure ventilation, that of the shivering dog respiring warm humidified air spontaneously increased outstandingly, shivering thermogenesis made the rewarming rates increased obviously.
Airway rewarming is a method conducive to rewarming of hypothermia. When the body is shivering, the metabolic heat production increases obviously, that makes the rewarming rate increase markedly. So the shivering must be inhibited in order to eliminate the interference of shivering thermogenesis when the effects of airway rewarming are detected.
探讨寒颤对气道复温的影响。
将麻醉后的犬浸入冷水中并给予阿曲库铵以抑制寒颤，建立无寒颤的低温犬模型。模型犬分别吸入温暖的全湿化（40 - 45摄氏度，相对湿度99.9%）空气和室温空气（19±1摄氏度，相对湿度30% - 75%）进行复温，每次2小时，不同温度空气吸入顺序随机安排。复温4小时后，使松弛的犬通过正压通气吸入温暖湿化空气以恢复自主呼吸。然后犬继续自主吸入温暖湿化空气，直至犬的食管温度（Te）和直肠温度（Tr）达到与浸入水中时相同的度数。实验过程中通过间接测热法检测代谢产热。
（1）寒颤被抑制时，吸入温暖湿化空气2小时，犬的Tr和Te每小时分别升高0.26 - 0.39摄氏度和0.44 - 1.11摄氏度；吸入室温空气2小时，犬的Tr和Te每小时分别降低0.24 - 0.51摄氏度和0.58 - 0.67摄氏度。犬的Tr和Te变化与不同温度空气吸入顺序无关。（2）有寒颤的犬自主吸入温暖湿化空气时，Tr和Te的复温速率分别为2.26 - 2.33摄氏度/小时和1.96 - 2.38摄氏度/小时，比寒颤被抑制的犬更快。（3）与寒颤被抑制的犬通过正压通气吸入温暖湿化空气的代谢产热相比，有寒颤的犬自主吸入温暖湿化空气的代谢产热显著增加，寒颤产热使复温速率明显加快。
气道复温是一种有利于低温复温的方法。当身体发生寒颤时，代谢产热明显增加，使复温速率显著提高。因此，在检测气道复温效果时，必须抑制寒颤以消除寒颤产热的干扰。
